The scattering of x rays and neutrons from rough surfaces is calculated. It split into specular reflection diffuse terms. These are calculated in the first Born approximation, explicit expressions given for whose roughness can be described as self-affine over finite length scales. Expressions also liquid surfaces, where it shown that ``specular'' reflections only exist by virtue a cutoff to mean-square height fluctuations. randomly oriented studied typical small-angle experiment. how various...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular monolayers and films. A panel report for the Materials Sciences Division of Department EnergyJerome D. Swalen, L. Allara, J. Andrade, E. A. Chandross, S. Garoff, Israelachvili, T. McCarthy, R. Murray, F. Pease, Cite this: Langmuir 1987, 3, 6, 932–950Publication Date (Print):November 1, 1987Publication History Published online1 May 2002Published inissue 1 November...

When a smectic-$A$ phase is composed of chiral molecules, it exhibits an electroclinic effect, i.e., direct coupling molecular tilt to applied field. The pretransitional behavior the effect in $A$ used study critical near second-order, smectic-$A$---smectic-$C$ transition. This measured by monitoring change birefringence sample as causes molecules. A large measured, and constants describing are determined.

The enhancements of normal Raman scattering, resonance and fluorescence from molecules adsorbed on identical, well-characterized, silver-island films are reported. enhancement arises the electromagnetic interaction between electronic plasma silver islands. A hierarchy ratios is found, with typical values 105 for RS, 103 RRS 10−1 to 10 fluorescence, depending quantum yield molecular fluorescence. model, developed heuristic grounds substantiated using density matrix formalism, describes light...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTContact angle hysteresis on heterogeneous surfacesLeonard W. Schwartz and Stephen GaroffCite this: Langmuir 1985, 1, 2, 219–230Publication Date (Print):March 1985Publication History Published online1 May 2002Published inissue 1 March 1985https://pubs.acs.org/doi/10.1021/la00062a007https://doi.org/10.1021/la00062a007research-articleACS PublicationsRequest reuse permissionsArticle Views1755Altmetric-Citations226LEARN ABOUT THESE METRICSArticle Views...

Over the past decade and a half, analyses of dynamics fluids containing moving contact lines have specified hydrodynamic models in rather small region surrounding (referred to as inner region) which necessarily differ from usual model. If this were not done, singularity would arisen, making it impossible satisfy contact-angle boundary condition, condition that can be important for determining shape fluid interface entire body (the outer region). Unfortunately, nature within under dynamic...

We measure the macroscopic capillary rise height of water on a chemically heterogeneous solid surface in presence vibrational noise. The amount relaxation contact angle depends mechanical characteristics as well energy vibrations. recede and advance angles are functions vibration level. Large enough levels mitigate hysteresis. Microscopic line configurations depend strongly microscopic wettability variation surface. Our study has implications for measurements normal environments retention...

We examine the wetting properties of surfaces coated by organic monolayers having varying degrees chemical damage. Macroscopic contact angles and angle hysteresis energy serve as one characterization surfaces. Measurement line structure to micron resolution over centimeter lengths serves another characterization. also dynamics jumps along in different regions around a loop. investigate scaling pinning elastic energies influence gravity dictating roughness at various length scales. measure an...

Both the spectral dependence and magnitude of excitation spectra surface-enhanced Raman scattering are found to be quantitatively related absorption for silver-island films. This relationship is maintained even when local electromagnetic enhancement at islands varied by coating film with a layer absorbing dye molecules. The results illustrate simple experimental way determine independently role electronic plasma resonances in process on these films shed new insights into details interactions...

We examine the microscopic pinning of a contact line on single heterogeneity. find that many features this behavior are predicted by models based same energy functionals which describe macroscopic angle hysteresis surfaces with such imperfections. As defect emerges from undistorted line, pins, increasingly distorts, slides across defect, and then jumps back to an position. The distortion stably pinned is described logarithmic dependence. While force depends microstructure, elastic restoring...

The fluorescence of molecules on silver-island films exhibits nonexponential decay and is several orders magnitude more rapid than a silica surface, while the total emission intensity slightly increased. This behavior results from electromagnetic coupling between fluorescing plasmon resonances silver islands. We obtain good agreement with model that uses same theory for as has been used to account surface-enhanced Raman scattering.

Des monocouches de stearate cadmium ont ete preparees selon la methode Langmuir-Blodgett. Un ordre orientationnel des liaisons molecules tensioactif a mis en evidence. Les correlations orientationnelles s'etendent sur distances macroscopiques (∼1 mm), alors que les translationnelles decroissent une longueur dizaines d'angstroms. L'axe est incline par rapport normale surface mais direction l'inclinaison aleatoire. Nos mesures diffraction electronique suggerent agregation chaines aliphatiques...

The contact angle is an important boundary condition needed to predict the shape of menisci. However, its measurement and use under dynamic conditions are not well understood. We have measured menisci very close moving lines over a suite geometric shapes for macroscopic excellent agreement between theory experiment establishes that proposed characterizes only materials system. Implications microscopic physics controlling angles explored.

Real surfaces are rough and chemically heterogeneous on many length scales wetting phenomena these affected by this inhomogeneous nature. We have used x-ray reflectivity to examine the structure of static precursing films which precede macroscopic meniscus water glass. examined thickness film, roughness interfaces bounding conformality or correlations between features interfaces. The film consists three basic components: bulk meniscus, a thin (≤100 Å) has sudden termination, beyond that,...

We have used Mie theory to account for the features of transmission spectra dye-coated silver-island films. The unusual behavior arises from effect dispersion and damping optical response absorbing coating on structural resonances silver islands. Our modeling indicates that power dissipation in dye is enhanced compared with deposited a nonresonant structure. These results help elucidate excitation mechanisms Raman fluorescent emission adsorbates at rough interfaces.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface-enhanced Raman scattering by molecules adsorbed on aqueous copper colloidsJ. A. Creighton, M. S. Alvarez, D. Weitz, Garoff, and W. KimCite this: J. Phys. Chem. 1983, 87, 24, 4793–4799Publication Date (Print):November 1, 1983Publication History Published online1 May 2002Published inissue 1 November 1983https://pubs.acs.org/doi/10.1021/j150642a007https://doi.org/10.1021/j150642a007research-articleACS PublicationsRequest reuse...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrigins of the Complex Motion Advancing Surfactant SolutionsB. Frank and S. GaroffCite this: Langmuir 1995, 11, 1, 87–93Publication Date (Print):January 1995Publication History Published online1 May 2002Published inissue 1 January 1995https://pubs.acs.org/doi/10.1021/la00001a018https://doi.org/10.1021/la00001a018research-articleACS PublicationsRequest reuse permissionsArticle Views363Altmetric-Citations69LEARN ABOUT THESE METRICSArticle Views are...

In the cystic fibrosis (CF) lung, airway surface liquid (ASL) volume is depleted, impairing mucus clearance from lung and leading to chronic infection obstruction. Several therapeutics have been developed that aim restore normal hydration CF airway, yet preclinical evaluation of these agents hindered by paucity methods available directly measure ASL. Therefore, we sought develop a straightforward approach ASL would serve as basis for standardized method assess mucosal using readily...

Surface tension gradient driven, or "Marangoni", flow can be used to move exogenous fluid, either surfactant dispersions drug carrying formulations, through the lung. In this paper, we investigate spreading of aqueous solutions water-soluble surfactants over entangled, mucin that mimic airway surface liquid We measure movement formulation by incorporating dyes into while flows solution subphase using tracer particles. forces and/or Marangoni stresses initiate a convective rheologically...

A concentration gradient of surfactants in the presence polymers that non-covalently associate with will exhibit a continually varying distribution complexes different composition, charge, and size. Since diffusiophoresis colloids suspended solute depends on relaxation interactions between solutes particles, polymer/surfactant complexation alter rate driven by surfactant gradients relative to observed same absence polymers. microfluidic device was used measure solutions containing sodium...

The energy of a monolayer surfactant on surface is calculated as function the orientation tails. structure determined by competition between spacings preferred polar heads and nonpolar As head-tail mismatch, we find region no molecular tilt, one uniform tilt. In tilted state, solitonlike defects resembling micellar clusters are stabilized entropy or finite-size effects.